Formaldehyde → [(2,4-Dioxoimidazolidin-1-yl)methyl]phosphonic acid

Beteiligte Stoffe

Reaktionsschritte

A 500 ml round-bottom flask was equipped with a thermometer, condenser, magnetic stirrer, and heating mantle. Into the flask was charged, under nitrogen, 10.0 g (0.100 mole) of hydantoin, 3.2 g (0.10 mole) of paraformaldehyde (purity: ca 95%), and 60 ml of anhydrous acetic acid. The resulting mixture was heated at reflux for 0.75 hour and then cooled. To the resulting clear solution was added 8.5 g (0.100 mole) of 97% phosphorous acid and 30.6 g (0.300 mole) of acetic anhydride. The reaction mixture was heated to reflux over 1.2 hours and held at reflux for another 0.1 hour. (A white solid precipitated early in the heating period and then redissolved toward the end.) The reaction mixture was cooled somewhat, and 150 ml of water was added to it. The resulting solution was heated at reflux for 2.0 hours, cooled, and vacuum stripped at 70° C. to give 21.4 g of crude 1-(phosphonomethyl)hydantoin as an oil. Quantitative analysis by hplc showed the yield of 1-(phosphonomethyl) hydantoin to be 46%.

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